Spraying method and apparatus to lubricate punch surfaces of tabletting machines



Aug. 12, 196

C. SEBASTIAN! SPRAYING METHOD AND APPARATUS T0 LUBRICATE PUNC SURFACES OF TABLETTING MACHINES 3 Sheets-Sheet 1 Filed April 19, 1966 INVENTOR CARLO SEBASTIANI ,WMafWMa ATTORNEYS Aug. 12, 1969 c. SEBASTIANI 3,

SPRAYING METHOD AND APPARATUS TO LUBRICATE PUNCH SURFACES OF TABLETTING MACHINES Filed April 19, 1966 3 Sheets-Sheet 2 INVENTOR CARLO SEBASTIANI ATTORNEYS 1969 c. SEBASTIANI 3,461,195

SPRAYING METHOD AND APPARATUS TO LUBRICATE PUNCH SURFACES 0F TABLETTING MACHINES Filed April 19, 1966 3 Sheets-Sheet 3 FIG. 4A

INVENTOR CARLO SEBASTIANI BY 77% amt ATTORN EYS United States Patent O 6 Claims ABSTRACT OF THE DISCLOSURE A lubricating apparatus for applying lubricating powder to the punches of a single station tablettingmachine operating in timed relation-with the feed chamber of the machine to apply the lubricating powder to the lower punch before the compression space is filled with the tablet forming blend and to the top of the tablet forming blend in the compression space after the blend has been fed into the compression space.

The present invention relates to an apparatus for producing effervescent, fully water-soluble tablets, the surface of which is solid and smooth, so that they may be packed in tubes without any paper wrapping. More particularly, this invention relates to an apparatus for apparatus for applying lubricatiing powder to the punch surfaces of tabletting machines in order to produce tablets which are more stable and less friable than those produced by any other known system.

Prior .methods and apparatus with such a scope were substantially based on the principle of processing in surroundings having a very low relative humidity (less than and temperatures (less than C.). By such methods, the result was, however, obtained for some powder compositions only and the necessary low values of air conditioning may be reached only through special and expensive installations.

It has now been found that, by two particular process conditions, it is possible to overcome the most important disadvantages of the prior system and that is first to cover with proper plugs the free ends of the two punches of the tabletting machine and second to lubricate properly the free faces of said plugs to produce tablets having a smooth and solid surface.

The plugs must, however, be formed of a plastic material of the acrylic resin class, as such a material is the only plastic material which was found to produce tablets having the desired smooth .and solid surface, while any other conventional plastic material, such as Teflon, natural rubber and the like, does not give said surface and the tablets produced have an irregular and rough surface. On the other hand, the proper lubricating of said plug free ends allows working at a relative humidity not above and temperature not above 30 C.

Accordingly, the main object of the present invention is to provide an apparatus for producing effervescent, fully water-soluble tablets as previously described, by employing any kind of effervescent blend without special air-conditioning installation and by using conventional tabletting machines, both of eccentric or rotary type, to which said apparatus will be applied.

As provided for, the free ends of the machine punches are previously covered by said plugs, which are properly lubricated by spraying a powder lubricant at suitable moments during working.

Other objects, features and advantages of the present invention will become apparent to those skilled in the .art

Patented Aug. 12, 1969 from the following description and the attached drawings, in which is illustrated, by way of example, only a preferred embodiment of the invention. In the drawings:

FIG. 1 is a diagram view of the main connected component means of this invention apparatus.

FIGURES 2A-2C are, respectively, plan and crosssectional views along the lines a-a and b-b of a spraying and lubricating chamber provided for said apparatus.

FIGURES 3A-3B are front elevational and fragmentary sectional views of the upper and lower punch heads of a tabletting machine, the free ends of which are properly covered by acrylic resin plugs.

FIGURES 4A-4D are the different positions of FIG. 2 chamber through the first four compression strokes.

In FIG. 1 are shown only the most important component means of the apparatus, i.e. powder lubricant tank 10, spraying and lubricating chamber 11 attached to the tabletting machine shoe 12, microswitch 13 and electric valve 14, the latter two comprising the timing means between the lubrication and the compression strokes. A flexible plastic pipe (not shown) is provided to connect tank 10 to lubricating chamber 11. It will be understood by those skilled in the art, that the embodiment here illustrated relates to a single station tabletting machine of the eccentric type, where only one spraying and lubricating chamber 11 for applying lubricating powder to the punches is provided.

To spray the suitable powder lubricant a conventional air-compressor or an inert gas bottle, such as nitrogen, may be used.

The operation of the apparatus herein illustrated may be briefly explained as follows by referring particularly to the first four compression strokes which are shown in FIGURES 4A-4D. When spraying and lubricating chamber 11 is in the position of FIG. 4A, microswitch 13 (FIG. 1) opens electric valve 14 and a spray of the lubricant is obtained, by a sprayer not shown, on the free surface of the plug 17 which covers the head of lower punch 15 (FIG. 3B). By passing from the position of FIG. 4A to the position of FIG. 4B, a cylindrical compression chamber 19 will be formed wherein the suit-able effervescent blend to be compressed is fed by the feed chamber 20 of the machine shoe 21. In the following position of FIG. 40, electric valve 14 is again opened to lubricate indirectly the plug free end of the upper punch by applying the powder lubricant on the free face of the formed blend cylinder 22 to be compressed, which is at that time enclosed within said compression chamber 19. The blend compression takes place in the position of FIG. 4D and, after removing the formed tablet, the cycle is repeated.

As aforesaid, the embodiment of the invention herein illustrated relates to an apparatus for a tabletting machine of the eccentric type, where only one of said spraying .and lubricating chamber 11 is used.

By using a tabletting machine of the rotary type, two of said chambers will be necessary, applied respectively before and after the filling position of the spraying and lubricating chamber. In this case, the second spraying and lubricating chamber may lubricate the free face of upper plug either indirectly, as explained for the tabletting machine of eccentric type, or directly on said free face of upper plug, by rotation of the sprayer through It will be understood that, within the purview of this invention, various changes may be made in the form, detail and arrangement of parts without departing from the scope of the invention as defined by the claims which follow.

What I claim:

1. A process for producing water soluble tablets on a single station tabletting a lower punch and a die with an inner surface comprising the steps, applying to the forming surface of the lower punch a lubricating powder; moving the lower punch relative to the die to define with the inner surface of the die a compression spacer having an open end; filling the compression space with a tablet forming blend; applying to the exposed surface of the tablet forming blend at said open end a lubricating powder; moving the upper punch from its retracted position towards the lower punch to form a tablet between the surfaces of the two punches and the inner surface of the die; moving the upper punch to its retracted position; and removing the tablet from the die.

2. In a single station tabletting maching having a die with inner walls, a lower punch defining together with the inner walls of the die a compression space, an upper punch movable into and out of said compression space and a feed chamber movable for intermittently feeding a tablet forming blend into said compression space, an apparatus for applying lubricating powder to said punches of the tabletting machine comprising storage means for lubricating powder; application means for said powder connected to said storage means, said application means being movable between a first position in which it is remote from said compression space and a second position in which it is located on top of said compression space; pressure means to force said lubricating powder into said application means for application to the punches; valve means for said pressure means; and control means for said valve means operating in time relation with the movement of the application means to deposit lubricating powder on the lower punch before the tablet forming machine having an upper and,

v.blend is fed into said compression space and on top of the tablet forming blend after said blend has been fed into said compression space."

3. An apparatus for applying lubricating powder as defined in claim 2 wherein the application means for the lubricating powder are connected to the feed chamber and movable in time relation therewith.

4. An apparatus for applying lubricating powder as defined in claim 2 wherein said pressure means for forcing the lubricating powder into said applicating means is a compressed gas.

5. An apparatus for applying lubricating powder as defined in claim 2 also comprising a pair of plastic plugs for the production of tablets with a smoothsurface, disposed at the ends of said lower punch and said upper punch for retention of the lubricating powder.

6. An apparatus for applying lubricating powder as defined in claim 5 wherein said plastic plugs are made of acrylic resin.

References Cited UNITED STATES PATENTS 1,105,838 8/1914 Richards 107-18 2,286,983 6/1942 Beutel. 2,965,946 12/1960 Sweet et al. 3,158,111 11/1964 Raff 107--17 X LAVERNE D. GEIGER, Primary Examiner E. J. EARLS, Assistant Examiner a US. Cl. X.R. 

